In general, an insulation capable of maintaining heat against conduction and radiation is commonly used in a wall body or a ceiling in order to achieve an insulating effect. Asbestos, rock wool, Styrofoam, and polyurethane foam are used as the insulation.
However, when this conventional insulation is disused, an environment is polluted and cancer-causing agents are generated. For the reasons, a vacuum insulation using glass fibers has recently been developed and used.
This vacuum insulation is configured by surrounding several sheets of films on the outside of a porous heartwood in order to reduce internal pressure and then processing sealing. The vacuum insulation has no danger of dust particles when disusing the vacuum insulation, and the vacuum insulation can be applied to building materials and home appliances, such as a refrigerant and an electric rice cooker.
The vacuum insulation includes a casing material configured to include openings therein due to a porosity (80% or higher) and formed of a gas-blocking film for maintaining the openings in a vacuum state, a heartwood made of a porous material, received in the openings of the casing material, and configured to form vacuum spaces, and a getter configured to adsorb gas and moisture.
The casing material can be formed of a film formed by laminating a multi-layer polymer and aluminum. The heartwood is made of glass fibers, glass wool, or a silica core on which pre-processing processes have been performed so that heartwood has specific hardness and a desired size. The getter is kind of an air absorbent and a moisture absorbent for absorbing gas and/or moisture that are present within the casing or newly introduced.
This conventional vacuum insulation, however, is problematic in that it is difficult to maintain a vacuum state due to gas generated from the heartwood and external moisture and gas. As a result, the getter is expensive, thereby increasing the unit cost of production.
Furthermore, there are problems in that it is difficult to manufacture the vacuum insulation because the heartwood made of glass fibers or glass wool experiences needling or thermal compression processes and the vacuum insulation has low initial performance because long glass fibers forming the glass fibers are crossed each other in a vertical, horizontal, or slope form.
Meanwhile, an insulation made of conventional short glass fibers is problematic in that the short glass fibers are detached from the insulation during a transport or construction process or when the insulation is used for a long time and the detached short glass fibers enter a respiratory organ, thus having a bad influence on the human body.